Position control system for counterweighted vehicle laundry top brush

ABSTRACT

A horizontal top brush for a vehicle laundering or finishing plant wherein a brush rotated by an hydraulic motor is mounted between the free ends of pivot arms carried by spaced vertical stanchions flanking a vehicle lane. Counterweight arms on the left and right sides of the wash lane have an axis of rotation which is spaced from the axis of rotation of the brush pivot arms. The counterweight arms are mechanically interconnected with the brush arms by sector gears, an arrangement which permits all of the brush and counterweight arms to lie on one side of the vertical support stanchions. The brush arms are slotted to permit the counterweight arms to pass through them. Brush position relative to the vehicle is varied as a function of brush motor reaction which in turn is a function of brush contact pressure or depth. Electromagnetic sensors on a torque arm carrying the brush motor casing sense angular displacement of the torque arm relative to the brush support arm and vary brush position to maintain a desired contact pressure.

RELATED APPLICATION

This application relates to copending patent application Ser. No. 08/635,583, COUNTERWEIGHTED VEHICLE LAUNDRY TOP BRUSH AND POSITION CONTROL SYSTEM THEREFOR, filed concurrently herewith.

FIELD OF THE INVENTION

This invention lies in the field of vehicle laundering apparatus. More particularly, the invention relates to a novel system for controlling the position of a vehicle treatment device such as a washing or polishing brush using position commands which are a function of brush drive motor reaction torque.

BACKGROUND OF THE INVENTION

Vehicle laundering and finishing systems using rotating brushes for cleaning and/or polishing the exterior surfaces of automotive vehicles are well known and in widespread commercial use throughout the United States.

A top brush; i.e., a brush having a horizontal axis of rotation which extends across a vehicle lane, is typically mounted on one end of a pair of counterweighted parallel pivot arms the angular positions of which determine brush elevation relative to a vehicle. The use of a beam having a fulcrum to support the brush at one end and counterweights at the other end permits the cantilevered weight of the brush and brush drive motor to be effectively neutralized and reduces the power required to reposition the pivot arms.

A treatment device such as a brush can also be rigged for pure vertical displacement and effectively counterweighted using cables and pulleys or the equivalent.

Vehicle top brushes are typically provided with automatic positioning systems which operate in the manner of a feedback control loop to cause the brush to follow the contours of a vehicle. Prior art positioning systems include electric eyes movable with the brush which scan across the path of vehicle travel and make/break a circuit which controls power to an hydraulic cylinder or electric motor which raises and lowers the brush. When the electric eye "sees" the vehicle, it switches power to the cylinder or motor to raise the brush. Determining when to lower the brush requires additional complexity.

Another type of brush positioning system uses the principle of sonar to monitor the elevation of the horizontal surfaces of the vehicle and reposition the brush to follow changes in surface elevation; i.e., a sonic signal is directed toward a vehicle surface and reflected back to the sonar transmitter. The distance from the transmitter to the vehicle is calculated as a function of the time required for an emitted signal to make a round trip to and from the vehicle and the brush is positioned accordingly. Sonar systems are expensive and require an angle near 90° between the transmitter and the target surface to properly read the reflected signal.

It is also known to control brush position as a function of the strain or twist in a brush center shaft, the strain being measured and converted into an electrical signal by strain gages. Because the strain gages are mounted on a rotating shaft, however, slip rings or the like must be provided to convey the strain signals to electronics modules mounted on a non-rotating element of the system and connected to the positioning motor.

SUMMARY OF THE INVENTION

In accordance with of the invention, proper brush contact depth with consequentially optimum laundering and/or finishing efficiency is maintained without the need for electric eyes or sonar type vehicle surface elevation sensors as the primary brush position control signal generator and without the need for slip rings or other devices to take electrical signals from a rotating shaft.

In general, this is accomplished by way of a system which monitors the reaction torque experienced by the motor which is employed to drive the rotating brush. The monitoring apparatus is not mounted on the rotating shaft and requires no special apparatus to convey electrical signals from a rotating environment to a non-rotating environment. The monitoring apparatus preferably develops a set of signal conditions representing (a) desired brush contact depth, (b) excessive contact depth, and (c) insufficient contact depth. These signal conditions are employed to actuate a power device such as an electric motor to reposition the brush so as to restore the brush contact pressure to the desired level.

In the embodiment hereinafter illustrated and described in detail, a vehicle top brush is mounted between parallel spaced apart pivot arms, one of which is provided with a torque arm which is permitted to pivot to a limited degree relative to the associated brush support arm around the brush axis of rotation. The motor which drives the brush has an impeller or other output member connected directly to the brush shaft and a casing which is mounted on the torque arm. The motor drives the brush in one direction against resistance created by friction as the brush contacts the vehicle; the greater the contact depth, the greater the friction. This friction creates a reaction torque which tries to drive the motor casing and the torque arm on which it is located in a direction opposite to brush rotation. The torque arm is interconnected with the associated pivot arm by a resilient device such as a spring or a hydraulic damper so as to provide a resistance to relative angular displacement which increases with displacement.

Accordingly, as brush contact depth increases, reaction torque increases tending to pivot the torque arm to a greater degree. Means are provided to generate signal conditions representing the degree of angular displacement between the torque arm and the adjacent brush support arm. A first signal condition is developed to represent desired brush contact depth or pressure. Second and third signal conditions are developed to represent insufficient and excessive contact depth respectively. All three signal conditions are used to control an electric motor to raise and lower the brush arm so as to maintain the desired position of the brush relative to the vehicle surface.

The invention is described hereinafter by reference to an illustrative embodiment in the form of a counterweighted top brush system for conveyor type vehicle laundry installations. It will be apparent to those skilled in the vehicle laundering and finishing arts that the inventions are, however, usable in both conveyor and rollover type operations and that the counterweighting system may be used with different position control systems and vice versa.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective drawing of a vehicle top brush counterweighted support system constructed in accordance with the invention;

FIG. 2 is a side view of a portion of the apparatus of FIG. 1 with the counterweight and brush in a brush-raised position;

FIG. 3 shows the FIG. 2 apparatus with the brush in a partially lowered position;

FIG. 4 is a top plan view of the apparatus of FIG. 1;

FIG. 5 is a perspective view of a detail of the position sensing apparatus;

FIGS. 6A-6C are side views of the position sensing apparatus in different positions relative to the brush support arm on which it is mounted representing different levels of motor reaction torque and brush contact depth; and

FIG. 7 is a block diagram of a position control system utilizing the signal conditions generated by the sensors in the apparatus of FIGS. 5 and 6A-6C.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENT Counterweight System

FIGS. 1-3 illustrate a compact, counterweighted support and positioning system for a top brush 10 in a conveyor type vehicle laundry having a lane 12 for travel of the vehicle through the laundry in the direction indicated by the arrow. The apparatus of FIGS. 1-3 is typically used in conjunction with other vehicle laundry system components including spray arches, side brushes, window brushes, wheel cleaners, rinse spray arches, dryer blowers, and the like.

The apparatus of FIGS. 1 through 4 comprise a pair of vertically oriented stainless steel support stanchions 14 and 16 disposed on opposite sides of the wash lane 12, the spacing between them being sufficient to permit the passage of a vehicle and provide clearance for system components. The stanchions 14 and 16 define a vehicle approach side which is to the left of the stanchions as viewed in FIG. 1 and a vehicle departure side which is to the right of the stanchions as viewed in FIG. 1. The stanchions are bolted to the floor and are of such size and strength as to be capable of bearing substantial compression and bending loads as will be apparent to those skilled in the relevant mechanical arts from the following description.

Support stanchions 14 and 16 are provided at the upper ends thereof with vertical plates 18 and 20. The planes of the plate 18 and 20 are parallel to one another and to the direction of vehicle travel. Plate 18 serves as the support for a brush support pivot arm 22 which extends outwardly in the direction of the departure side of the stanchions 14 and 16. A similar parallel brush support arm 24 is rotatably mounted on plate 20. The arms 22 and 24 are provided with suitable bearings so that they are pivotally rotatable about a common brush arm pivot axis 48 extending across the wash lane 12 at a height above lane 12 of about four feet.

Brush 10 has a center shaft 26 which is mounted in and through bearing boxes 28 and 30 at the free ends of the pivot arms 22 and 24 respectively. An hydraulic brush drive motor 32 is carried by the brush arm 24 the impeller of which is supplied with hydraulic fluid pressure by a pump (not shown) to rotate the brush 10 in the proper direction on demand. A motor 36 controls the position of the brush arms as hereinafter described in detail.

To reduce the power requirements of the motor 36 by effectively reducing brush weight, a pair of counterweight arms 38 and 40 are pivotally mounted to the plates 18 and 20 respectively for rotation in a vertical plane and about an axis defined by a jack shaft 46 which is connected between the arms 38 and 40 insures synchronism of the pivotal movement of the arms. Heavy metal counterweights 42 and 44 are carried at the free ends of the arms 38 and 40, respectively. All of the arms 22, 24, 38 and 40 extend into the departure side of the stanchions 14 and 16 and the paths of travel of the arms overlap as shown in FIGS. 2 and 3. The counterweights are selected such that the brush is slightly "heavy"; i.e., the brush would, in the absence of external inputs, tend to fall slowly downward under the force of gravity.

Arms 22 and 38 are mechanically interconnected by gears 47 and 49. Arms 24 and 40 are similarly interconnected by gears 50 and 52. The gears 47, 29, 50 and 52 are sectorial in shape and have meshing peripheral teeth such that movement of arms 38 and 40 in the downward direction, for example, produces a corresponding movement of arms 22 and 24 in the upward direction. The angle between the arm set 22 and 38, for example, varies as the arms move relative to one another.

Arm 22 is constructed of spaced, parallel beams 54 and 56 which define between them a center slot through which counterweight 42 and arm 38 can pass as the brush 10 is raised from the FIG. 1 position to the FIG. 2 position. Arm 24 is of similar construction, comprising beams 60 and 62 to allow counterweight 44 to pass through its center slot. While a hollow brush arm construction is preferred, offsetting the arms slightly to permit them to pass one another without interference is essentially an equivalent approach.

Hollow plastic shrouds 57 are disposed about the counterweights and arms as shown in FIG. 3 to prevent persons from placing hands, arms or tools between the arms as they progress through their overlapping paths of travel. Although shown only on one side of the assembly; i.e., around arm 40 in FIGS. 1 and 3, it will be understood that such a shroud is placed at each side of the assembly. The shroud 57 is secured to plate 20 and lies entirely inside of the center slot of the associated brush arm.

The drive motor 36 is located on a support plate 59 which is welded or bolted to stanchion 14. The motor output shaft drives an arm 61 having a pin 63 which bears against the side of the counterweight arm 38 to drive it in the downward direction; i.e., in a direction which raises the brush. This is essentially a one-way drive and a corresponding system is more fully described in U.S. Pat. No. 5,613,260, the disclosure of which is incorporated herein by reference.

Brush Positioning System

Referring now to FIGS. 5 through 7, a system for controlling the position of arms 22 and 24 as a function of the reaction torque of motor 32 will be described. As shown in FIG. 5, pivot arm 24 is formed by spaced, parallel beams 60 and 62 which straddle bearing box 30 at the free ends thereof. A "torque arm" 64 is mounted on beam 62 so that it may rotate relative to arm 24 about the axis of motor 32; i.e., about the axis of shaft 26. Motor 32 is mounted on torque arm 64 such that the motor casing and arm 64 are locked together. The impeller output shaft of the motor 32, however, is connected to motor shaft 26 either directly or via a gear box as is required for speed selection.

Because arm 64 can pivot relative to arm 24, the resistance to rotation created by friction between brush 10 and a vehicle tends to rotate arm 64 in a direction opposite brush rotation. This rotation is resisted and proportionally controlled by resilient damper 74 which functions as a spring; i.e., the greater the reaction torque, the greater the angular displacement of arm 64 relative to arm 24.

To determine the degree of relative angular displacement between the torque arm 64 and the brush pivot arm beam 62, electromagnetic proximity switches 66 and 68 are mounted on the torque arm 64 at different distances from the axis of shaft 26. The proximity switches 66 and 68 are furnished with AC line current by wiring (not shown) and work in association with ferromagnetic disks 70 and 72 which are mechanically secured such as by epoxy bonding to the surface of the beam 62 immediately under the proximity switches 66 and 68 when the torque arm 64 is aligned with the adjacent beam 62. The operation of the limit switches is such that they are in one output signal condition when the switch overlies its associated ferromagnetic disk and in an opposite signal condition when the limit switch body no longer overlies the ferromagnetic disk to a sufficient degree to establish a preset degree of electromagnetic coupling between them. The latter condition occurs as the torque arm 64 displaces away from a position of alignment with the underlying beam 62. The limit switch 68, because it lies at a greater distance from the center of shaft 26 than does the switch 66, is the first one to switch between signal conditions. By way of example, 10 degrees of rotation of arm 64 relative to arm 24 may toggle switch 68 whereas 20 degrees may be required to toggle switch 66.

The manner in which the signal conditions of the proximity switches 66 and 68 are utilized in the position control system in the apparatus of FIG. 1 is illustrated best in FIGS. 6 and 7. In FIG. 6A the torque arm 64 is in alignment with the underlying beam 62; i.e., there is no reaction torque generated by the action of the motor 32 on the brush and the reaction of the brush to the surface of the vehicle being laundered. Under this condition, the limit switch bodies 66 and 68 both lie in full registry with the associated ferromagnetic disks 70 and 72.

FIG. 6B represents an intermediate degree of reaction torque and a partial displacement of the torque arm 64 in the clockwise direction relative to the underlying brush support arm beam 62. In this condition, the limit switch 68 is displaced out of registry with the underlying ferromagnetic disk to the point that it has switched from the signal condition of FIG. 6A to the opposite signal condition. However, the limit switch 66, lying on a shorter radius from the center of rotation of motor 32 and brush shaft 26, is displaced to a lesser amount and remains in sufficient registry with the underlying ferromagnetic disc to maintain the first signal condition. The damper 74 is chosen such that the condition of FIG. 6B represents desired brush contact depth and pressure.

Looking to FIG. 6C, a high degree of reaction torque associated with great contact depth between the brush and the vehicle being laundered causes substantial clockwise displacement of the torque arm relative to the beam 62 and the condition of non-registry between both of the limit switches 68 and 66 and the underlying ferromagnetic disks 72 and 70 respectively. Accordingly, FIG. 6C represents a fully switched signal condition for both of the limit switches.

Reviewing, the conditions of the limit switches 66 and 68 in FIGS. 6A, 6B, and 6C defines a truth table which is easily implemented using a microprocessor or hardwired circuitry into a decoder for use in a controlled circuit. FIG. 6A shows both switches in the first signal condition; FIG. 6B shows one switch in each of the two signal conditions and FIG. 6C represents both switches in the opposite signal condition. If a switch having essentially aligned components is represented by a "1" and a switch having essentially non-aligned components is represented by the number "0," then the truth table is as follows:

    ______________________________________                                         1-1    =             insufficient contact pressure                             1-0    =             desired contact pressure                                  0-0    =             high contact pressure                                     ______________________________________                                    

In a control scheme, the signal condition 1-1 is set up to actuate the motor 36 so as to lower the brush 10 and increase the contact pressure with the vehicle being laundered. In the same system, the signal condition 1-0 represents satisfactory or desired contact pressure and the motor 36 is held stationary to maintain brush position. Finally, the signal condition 0-0 is set up to represent a brush reaction torque condition which actuates the motor 36 in a direction to raise the pivot arms 22 and 24 and decrease the brush contact pressure.

A control system adopting the aforementioned protocol is represented in FIG. 7. The sensors 66 and 68 produce electrical signals which are connected to a simple decoder circuit 76 which may, as mentioned above, be implemented with a microprocessor or a hard wire circuit. The decoded output, one of three signal conditions, is applied over appropriate signal lines to switch unit 78 which controls the direction of rotation of motor 36. Motor 36 drives arm 61 and counterweight arm downwardly, for example, to drive parallel arm 40 downwardly through jack shaft 46. Gears 50 and 52 raise brush pivot arm 24 to lift the brush. If the motor excitation is such as to drive motor 36 in the opposite direction, arm 61 moves away from arm 38 and allows the brush to fall. The result is a feedback type positioning system in which the signal condition 1-0 represented by the relative position of the torque arm 64 in FIG. 6B represents the desired contact pressure condition, the signal condition 1-1 represents insufficient contact pressure and the signal condition 0-0 represents too much contact pressure. The conditions of FIGS. 6A and 6C; i.e., 0-0 and 1-1 respectively, cause operation of the motor 36 in a direction which tends to reposition the brush 10 relative to the vehicle in a direction to restore the signal condition to the 1-0 state represented by FIG. 6B.

Operation

In operation, the system is placed in a home or standby condition awaiting the approach of a vehicle; the standby condition can be that represented by FIG. 1. As the vehicle approaches its presence can be detected by a wand or photoelectric device so as to start the brush motor 32 and drop the brush 10 to a position where it will engage the vehicle in the desired fashion. As the brush passes, for example, from the hood of the vehicle to the top of the vehicle, it encounters the windshield which causes an increase in contact pressure and an increase in reaction torque causing a change from the signal condition represented by FIG. 6B to the signal condition represented by FIG. 6C. The decoder 76 operates the motor 36 so as to lift the brush 10. The brush 10 is continuously varied in position to follow the contours of the vehicle so as to, for example, progress down the back light and across the rear deck of the vehicle and, where desired, down the rear vertical surface of the vehicle to the bumper level. A photoelectric device 80 is mounted on supports 14,16 to "anticipate" the rear window of the vehicle and release or drop the brush 10 early to maintain good coverage.

Although the illustrative embodiment of the inventions has been described with reference to a conveyor or tunnel type of vehicle laundry, it will be apparent to those skilled in the art that the features and advantages of the counterweighting and positioning control systems can also be used in combination with rollover or gantry type vehicle laundry systems wherein the vehicle is parked in the wash lane and the brush and support components travel on rails relative to the vehicle. Similarly, the features and advantages of the invention can be enjoyed in connection with a polishing brush as well as with wet wash laundering brushes of various types. Further, different apparatus may be substituted for the torque arm 64 and switches 66, 68 to determine reaction torque; for example, the arm 64 may be fixed to arm 42 at the right end as seen in FIG. 6 and equipped with strain gages to measure strain therein. A smaller arm, or at least an arm with a smaller section strategically located therein, could be used for this purpose. 

The invention claimed is:
 1. A system for controlling the position of a rotating brush relative to an object being contacted by the brush comprising:support means carrying said brush; a motor mounted to said support means and connected to drive the brush about an axis of rotation; selectively actuable power means for controlling the position of the brush relative to the object; means for sensing a reaction torque experienced by said motor when rotating said brush as applied to said support means and for producing signal conditions related thereto; and means connecting said signal conditions to the power means for controlling the position of the brush so as to tend to maintain a desired brush contact depth relative to the object.
 2. A system as defined in claim 1 wherein the means for sensing comprises a torque arm mounted to said motor for angular displacement relative to said support means; andmeans for determining angular displacement of said torque arm relative to said support means and for generating said signal conditions.
 3. A system as defined in claim 2 wherein said means for determining angular displacement of the torque arm comprises a pair of sensors disposed in part on said torque arm at spaced locations therealong for generating discreet signals representing the degree of angular displacement thereof relative to discreet and adjacent portions of the support means.
 4. A system as defined in claim 3 wherein the discreet signals from said sensors are related to the brush contact depth according to the following table:

    ______________________________________                                         1-1    =             insufficient contact pressure                             1-0    =             desired contact pressure                                  0-0    =             excessive contact pressure                                ______________________________________                                    


5. A system as defined in claim 2 wherein the brush drive motor has a casing and an output member rotatable relative to the casing, the output member being connected to rotate said brush and the casing being mounted on said torque arm.
 6. A system as defined in claim 1 wherein the support means comprises a pair of parallel, pivotable brush support arms for carrying said brush between free ends thereof; andmeans for counterweighting said brush support arms.
 7. A system as defined in claim 6 wherein said counterweight means comprises at least one counterweight support arm mounted for angular displacement relative to said support means; andgearing means interconnecting one of said brush support arms with said counterweight arm for synchronizing angular displacement thereof.
 8. A system as defined in claim 7 wherein both the brush support arm and the counterweight support arm extend from said support means in essentially the same direction relative to a vertical reference through the axes of rotation of said brush support and counterweight support arms.
 9. A system as defined in claim 7 wherein the counterweight means comprises a pair of counterweight arms mounted in spaced parallel relationship to one another and proximate respective brush support arms; anda synchronizer shaft connected between the counterweight arms to maintain the parallel relationship therebetween during displacement thereof.
 10. A system for controlling a position of a rotating brush relative to an object being contacted by the brush comprising:support means for carrying the brush; a motor for driving the brush about an axis of rotation and having a casing mounted to said support means; means for sensing an angular displacement of said motor casing relative to said support means and for producing signal conditions related to said angular displacement; and power means selectively actuable in response to said signal conditions to control movement of the brush so as to tend to maintain a desired brush position relative to the object.
 11. A system as defined in claim 10 wherein the means for sensing comprises:a torque arm mounted to said motor casing and angularly displacable relative to the support means; and means for determining angular displacement of said torque arm relative to a reference position and for generating said signal conditions.
 12. A system as defined in claim 11 wherein said means for determining angular displacement of the torque arm comprises a pair of sensors disposed in part on said torque arm at spaced locations therealong for generating discreet signals representing the degree of angular displacement thereof relative to discreet and adjacent portions of the support means.
 13. A system for controlling the position of a rotating brush relative to an object being contacted by the brush comprising:support means for carrying said brush; a motor for driving the brush in rotation; a torque arm mounted to the motor for angular displacement relative to the support means; a pair of sensors disposed in part on said torque arm at spaced locations therealong for generating signals representing the degree of angular displacement thereof relative to adjacent portions of the support means; power means actuable to control a position of the brush relative to the object; and means connecting said signals to said power means and actuating said power means so as to tend to maintain a desired brush contact depth relative to the object.
 14. A system as defined in claim 13 wherein the signals from said sensors are related to the brush contact depth according to the following table:

    ______________________________________                                         1-1    =             insufficient contact pressure                             1-0    =             desired contact pressure                                  0-0    =             excessive contact pressure                                ______________________________________                                    


15. A system as defined in claim 13 wherein the brush drive motor has a casing and an output member which is rotatable relative to the casing, the output member being connected to rotate said brush and the casing being mounted on said torque arm. 